The invention relates to a display device comprising a liquid crystal material between a first substrate provided with row or selection electrodes and a second substrate provided with column or data electrodes, in which overlapping parts of the row and column electrodes define pixels, drive means for driving the column electrodes in conformity with an image to be displayed, and drive means for driving the row electrodes. Such display devices are used in, for example portable apparatuses such as laptop computers, notebook computers and telephones.
Passive matrix displays of this type are generally known and, to be able to realize driving of a large number of rows, they are more and more based on the (S)TN ((Super)-Twisted Nematic)) effect.
In (S)TN liquid crystal display devices, the pixels react to the effective value (rms value) of the supplied voltage. The drive of liquids (pixels) reacting in this manner is described in Alt & Pleshko's article "Scanning Limitations of Liquid Crystal Displays", IEEE Trans. on El. Dev., Vol. ED 21, No.2, February 1974, pp. 146-155.
In these devices, one row is consecutively driven each time. When rapidly switching (S)TN liquid crystal material is used, there is relaxation of the directors within one frame period. This leads to loss of contrast and is sometimes also referred to as "frame response".
Notably in applications in display devices built into portable apparatuses (mobile telephone, laptop computers) the aim is to drive these apparatuses with a minimal energy. It is notably attempted to minimize the drive voltages as much as possible in these cases.